Method of producing chain-links



Jan. 12, 1954 e. B. SGDERLUND 2,665,547 METHOD OF PRODUCING CHAIN-LINKSFiled April 24, 1950 2 Sheets-Sheet 1 Z1211) [GE-Z01 6L5. S'cienlund1954 G. B. SODERLUND U ,6

METHOD OF PRODUCING CHAIN-LINKS Filed April 24, 1950 2 Sheets-Sheet 2lzi/ v ejvb-ol 6135;; den luQIzcZ Patented Jan. 12, 1954 'UNITED STATES-PATENT OFFICE METHOD OF PRODUCING CHAIN-LINKS Gustav B.-S-iiderlund,Stockholm, Sweden Application April 24, 1950, Serial No. 157,644

1 Claim. 1

The present invention relates to a method of producing chain-links,particularly so-called Ewart-links.

The purpose of the invention is to create a method of producing linkshaving higher strength values and with greater exactness than has so farbeen possible, so that such links may even be used in transmissions,where great demands are made to strength and to quick and silentoperation.

Hitherto such links have been produced mainly according to the methodsmentioned below, viz.: In the first and oldest one, the initial materialis white pig iron, which is cast and annealed. The second method is tobend a piece of wire in such a manner that it forms a rectangular link.In the third method the initial material is profile-rolled steel, fromwhich link-blanks are punched out and then cold-bent and tempered. Sinceno further plastic deformation of the hot ingot takes place after it hasleft the rollers, it is easily realized that the links must be punchedout of the same in such a manner that the direction in which thestresses will act in the ready links, forms right angles with thedirection of rolling and thus also with the direction of the fibers inthe hot ingot, and furthermore the subsequent cold-bending of the linktongues will reduce the strength thereof still more.

These drawbacks are effectively eliminated by the use of a processaccording to the present invention, which is substantially characterizedtherein that the link-blanks are punched and cut out of a strip withpreferably rectangular section in such a manner that the direction inwhich the stresses will operate in the ready links coincides with thedirection of rolling, whereupon th link blanks are again heated andforged and, after having been subjected to ordinary annealing andhardening processes, they are subjected to mechanical working,preferably in a draw bench, so that the ready links obtain high strengthvalues and good fit.

The invention is described in the following text with reference to theaccompanying drawings, in which Fig. 1 shows diagrammatically theprevious process for producing links of the kind concerned in thisapplication in which process rolled steel constitutes the initialmaterial. Fig. 2 illustrates how the punching and cutting takes placeaccording to the present invention. Figs. 3a and 3?) show in section twolink-blanks (4, 5) undergoing the forging operation. Fig. 4, finally,shows how the contact surfaces of the links may be given an exact shapeby means of a scale removing tool (for instance a broach).

It has been mentioned already in the preamble that the methods Workingwith bending of wire or with casting are beset with many drawbacks, andthat because in the third method the links according to Fig. 1 are cutacross the direction of the fibers, the strength properties of thematerial cannot be fully utilized, besides which the tongue I must becold-bent the least bit. On the other hand, according to the processillustrated in Fig. 2, the direction in which the drawstresses will actin the ready links coincides with the direction of rolling, as indicatedin the figure, and thus also with the grain of the material. It is alsoapparent from Figure 2 that a plurality of rows of spaced holes 2 arepunched transversely and longitudinally of the strip and simultaneouslya plurality of rows of spaced smaller holes 3 are spaced transverselyand longitudinally of the strip with one row of small holes transverselypositioned between pairs of transverse rows of the larger holes and withone row of small holes longitudinally positioned between adjacentlongitudinal rows of the larger holes, said smaller holes being offsetfrom the larger holes in longitudinal and transverse directions.Immediately after or simultaneously with the punching, the strip is cuttransversely through the small holes to provide blocks containing aplurality of link blanks side by side and end to end with each havingtongue and pin portions.

As the cutting takes place simultaneously with or immediately after thepunching, the material is not at once divided into single links but inblocks containing for instance at least two links side by side and twolinks in length.

The above-mentioned direction of the link material relatively to thedirectionof rolling is made possible by a renewed heating and forging(Fig. 3) taking place after it has been rolled and punched, so that thelinks are given the desired section, i. e. the tongues 6 and the pins '1are formed.

During the subsequent mechanical working, which for instance may beffected with a breach, the contact surfaces 8, 9 of the links accordingto Fig. 4 finally are given the exact shape which is a condition for arapid and silent operation. The final cutting of the links (along thelines A-A and BB in Fig. 2) is not effected until the above-mentionedoperations have been accomplished. The number of links united into onblock may be varied within certain limits, thus it has appeared that sixto twelve links in each block is a suitable number.

It is quite obvious that this division into blocks involves greatadvantages. Among other, the

number of clamping and sorting operations will be highly reduced, whichsimplifies the manufacture of the links and reduces the costs connectedtherewith. It is also obvious that other working processes and machinesmay be used by those skilled in the art in the method of manufacturedescribed above without abandoning the idea and the scope of theinvention. Therefore, the same is only confined as disclosed in theaccompanying claim.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

In the method of manufacturing chain links of the kind having tongue andpin portions with essentially cylindrical contact surfaces, the stepsconsisting in rolling a metal strip to preferably rectangularcross-section so that the direction in which stresses will appear in thefinished links coincide with the direction of rolling, punching aplurality of rows of spaced holes transversely and longitudinally of thestrip and simultaneously punching a plurality of rows of spaced smallerholes transversely and longitudinally of the strip with one row of smallholes transversely positioned between pairs of transvers rows of thelarger holes and with one row of small holes longitudinally positionedbetween adjacent longitudinal rows of the larger holes, said smallerholes being ofiset from the larger holes in longitudinal and transversedirections, cutting the strip transversely centrally through the smallholes to provide blocks containing a plurality of link blanks side byside and end to end with each having tongue and pin portions, reheatingand press forging said blocks in order to shape a tongue and a pinportion at each blank, annealing and hardening the blocks and machiningthem to provide accurate contact surfaces at the tongue and pin portionsand finally dividing the blocks into individual links along longitudinallines passing centrally through said small holes and along transverselines passing centrally between each of the rows of said pairs of rows.

GUSTAV B. SijDERLUND.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 393,912 Locke Dec. 4, 1838 457,583 Goldie Aug. 11, 1891673,747 Howe May '7, 1901 1,670,758 Witherow May 22, 1928

